


But if I know you

by notallballs (notallbees)



Category: Haikyuu!!
Genre: Alpha/Beta/Omega Dynamics, Cuddling & Snuggling, Dubious Consent, First Time, Kissing, M/M, Mating Cycles/In Heat, Nesting, Non-Traditional Alpha/Beta/Omega Dynamics, Omega Iwaizumi Hajime, Omega Oikawa Tooru, Omega/Omega, Sleepovers, Sleepy/Unconscious Sex, Somnophilia
Language: English
Status: Completed
Published: 2018-05-07
Updated: 2018-05-07
Packaged: 2019-05-03 17:59:04
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 3,067
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/14574489
Author URL: https://archiveofourown.org/users/notallbees/pseuds/notallballs
Summary: Hajime is half asleep, dozing gently, when Oikawa moves against him with a low, soft sound. His hand grips Hajime's waist, breath hot against the back of his neck, and Hajime shivers.His first instinct is to shake him off, but Oikawa only sighs and presses closer, his knees fitting against Hajime's like they're puzzle pieces slotting together.Iwazumi and Oikawa have started keeping each other company during their heat cycles. One night it goes a little too far.





	But if I know you

**Author's Note:**

  * For [mousecat](https://archiveofourown.org/users/mousecat/gifts).



> Sometimes self-care is writing stupid abo fics??
> 
> Omegas (mostly) have vaginas deal with it.
> 
>  
> 
>  **Warning:** See the end notes for more detailed thoughts on omegaverse anatomy and **warnings**.

"Iwaaa," Oikawa whines down the phone at him. "Come over, Mama said you can stay."

Hajime rolls his eyes. Oikawa is always clingy when he's getting his heat, but he's also _way too hot_ , and it makes him a nightmare to sleep next to. "No way. Tomorrow's my lie in, I don't want you kicking me all night because you can't sleep."

"I'll be good, I promise," Oikawa says quickly. "Please, Iwa-chan? I thought we could do _that thing_ again."

Closing his eyes, Hajime flops back on his bed. The past few times one of the other of them has been in heat, or near enough, they've taken to keeping each other company, snuggling for comfort. Hajime covers his face, remembering the last time Oikawa stayed over, when Hajime had been in the middle of his heat. 

"Alright, if you want," he mumbles into his hand, and ends the call before Oikawa can say something irritating. 

 

—

 

Oikawa's parents are both home when Hajime turns up with his pyjamas and toothbrush hastily stuffed in his school bag. He spots them through the window before he lets himself in, and he hopes they won't want to talk to him. All he's been able to think about all afternoon is Oikawa, and how much he wants to kiss him until his face hurts.

"Tooru's upstairs, Hajime-chan!" Oikawa's mother calls out to him. 

"Thanks, Auntie!"

He pounds up the stairs, taking them two at a time, and bursts into Oikawa's room at the end of the hall.

Oikawa is lying on his bed with his phone held above his face, but at the sound of his door slamming open he drops it in surprise. The phone smacks him on the nose, then slithers down and bounces off the edge of his futon.

"Iwa-chan!" Oikawa yelps in outrage. He reaches up to prod his nose, continuing in a nasally tone. "Don't frighten me like that."

"A little scaring keeps the heart young," Hajime says, slamming the door shut behind him. "Not that you need to get any younger, you big baby."

Oikawa squawks at him, but the complaint is more subdued than usual. He retrieves his phone, then lifts his blanket and shimmies underneath it, burrowing down until only his hair is visible. 

Hajime takes the opportunity to change into his pyjamas while Oikawa is distracted, but just as he steps out of his jeans, Oikawa emerges from his nest and blinks up at him. 

"Creep," Hajime mutters, turning away to grab for his sweatpants. 

As he's turning them the right way out, Oikawa snakes a hand out and grabs hold of his ankle. "Come cuddle me, Iwa-chan," he whines. "I'm miserable."

"You're a pain in the ass," Hajime mutters. He tugs his leg free of Oikawa's limpet grasp, and pulls on his sweatpants before there are any more interruptions. He's never been shy of being naked around Oikawa before, but it's been different since they first kissed. A new energy between them that charges every familiar touch with electricity. "Let's watch a movie," Hajime says, reaching for his bag. 

It's easier with a distraction, an excuse to get close to each other. Oikawa's scent is heavy in the air, stronger when Hajime finally crawls into his futon with him and cuddles close. He drapes his arm around Oikawa's shoulders, and Oikawa finally stops grumbling and rests his head on Hajime's shoulder, sliding an arm around his waist.

They only make it about halfway through the movie before Oikawa turns his head, and Hajime dips his chin, and then they're kissing. Oikawa sighs into it and pulls Hajime closer, reaching up to run fingers through his hair. Hajime worries that he's not as good a kisser as Oikawa, who's had a lot more practice, but Oikawa doesn't seem to mind. And besides, they've had plenty of practice in the past few weeks. 

Oikawa rolls onto his back, pulling Hajime with him, and slides a hand up the back of his t-shirt. Usually all they do is kiss, but Oikawa's more handsy when his heat is coming on. The end of the movie comes and goes without them noticing, until Hajime finally pulls away with a groan, his mouth feeling raw and swollen, his underwear uncomfortably damp. 

"We should probably stop," he mumbles, pulling his t-shirt back into place as he sits up again. He hopes nobody will notice the bite mark he's left on Oikawa's neck.

"Mmm," Oikawa hums dreamily, hugging his arm tightly around Hajime's waist. "Thanks, I feel better."

"Good for you," Hajime grumbles, shifting uncomfortably. "I don't."

Oikawa huffs with laughter. "Then do it, I don't care."

"No!" Hajime yelps, shoving him away. "That'd be weird."

"Mmf," Oikawa mumbles, face buried in his pillow. "If you say so, Iwa-chan."

Hajime turns away, his face hot. "I'm gonna brush my teeth."

Oikawa snorts. "Of course you are."

"I said I wasn't gonna do that!"

Hajime goes into the bathroom and splashes some cold water on his face and neck. He has red marks from Oikawa gnawing at his shoulder, but probably nothing that'll leave a lasting mark. He hesitates for a moment before picking up Oikawa's body spray and dousing his t-shirt with it, hoping it'll at least partly cover up the scent of them nesting together.

As soon as he's done, Oikawa flounces past him and into the bathroom with a wink, before closing the door behind him. Hajime growls, but Oikawa only laughs, knowing that he doesn't really mean it. Alone in Oikawa's room, Hajime lays out the guest futon and gets himself ready for bed. He's still achy and damp between his thighs, but he tries his best to ignore it, and doesn't let himself think about what Oikawa's getting up to in the bathroom. 

Finally Oikawa returns, switching off the light before getting into his own bed. Hajime turns over, but Oikawa isn't discouraged, and snuggles up against his back, right at the edge of his own futon. 

"Goodnight, Iwa-chan," Oikawa whispers. 

"Go to sleep, you big baby."

Oikawa hums softly. "I didn't jerk off, you know."

"I don't care."

"I wish I had, I'm too wound up to sleep."

Hajime's neck is hot. "Try," he snarls. 

For a little while, they do try. Hajime should have expected that Oikawa wouldn't try very hard. 

Hajime is half asleep, dozing gently, when Oikawa moves against him with a low, soft sound. His hand grips Hajime's waist, breath hot against the back of his neck, and Hajime shivers. 

His first instinct is to shake him off, but Oikawa only sighs and presses closer, his knees fitting against Hajime's like they're puzzle pieces slotting together. Hajime opens his mouth, but Oikawa makes another soft noise before he can speak, and grinds against his ass slowly.

Hajime's eyes snap open. "Oikawa—" 

Instead of answering, Oikawa keeps grinding against him, so that Hajime can feel Oikawa's clit straining in his pyjama pants, the heat of his cunt behind it. 

Hajime opens his eyes wide and stares at the wall. He knows he ought to say something, but if he does, then Oikawa might stop. Hajime's own shorts are getting damp, pleasurable anticipation radiating hot and overwhelming from the centre of his cunt. 

Tentative, Hajime braces his hand against the futon and pushes back, grinding against Oikawa's crotch. His breath stutters out of him at the unfamiliar sensation, and Oikawa's moan stirs the hair on his nape, his hand gripping Hajime's hip more tightly. They've never gone as far as touching before when they kiss, not like this. Normally Hajime waits until Oikawa has gone home or fallen asleep to take care of himself, and he's never been brave enough yet to ask Oikawa if he does the same.

Suddenly, it's all Hajime can think of. Oikawa in his bed, stroking his swollen clit, maybe fingering himself, maybe even thinking about Hajime while he rolls around in his own scent. 

"Oi—Oikawa," Hajime manages. 

Oikawa hums, his mouth soft against Hajime's bare shoulder. Sighing, Hajime rubs back against him, harder than before. There's an ache in his cunt and he's _dripping_ with slick, steadily soaking his underwear. He wonders if Oikawa is the same, if maybe he could reach behind him and find out. 

Oikawa's hand slides up, cupping Hajime's chest and squeezing. Encouraged, Hajime reaches behind him, his hand shaking as he slides it between their bodies. He touches Oikawa through his underwear, gentle at first, and then he presses in with more ardour, his mouth going dry at the way Oikawa's clit surges and pushes against his palm. Hajime fumbles at the waistband of Oikawa's underwear, slipping his hand inside and reaching down to feel the slippery velvet of his cunt, wet heat that tugs at him, beckoning him deeper. Oikawa's scent is so strong now, sweet and tantalising as he slips properly into his heat, and more of it rolls up as Hajime touches him. Hajime's fingers skid and _squish_ into that delicious warmth, and he licks his mouth, wondering what it would be like to _taste_.

"Iwa-chan," Oikawa sighs, a barely audible string of mumbling. "Iwa-chan—"

"Oikawa, can I—"

"Mmmm—"

Hajime retracts his hand and rolls over in his futon. His fingers are wet and sticky, and he almost puts them in his mouth, but he can't face the thought of Oikawa seeing him do that. Oikawa has flopped onto his back, his chest rising and falling quickly and his arms spread uselessly at his sides. Looking at him is too much; Hajime moves closer and tucks his face into Oikawa's neck as he moves his hand into Oikawa's underwear again. He sinks two fingers into Oikawa's cunt, hiding a choked noise in his neck at how good it feels, new and familiar all at once. Slick coats the palm of his hand and he grinds down on Oikawa's clit, rubs a circle with the heel of his hand. 

Oikawa makes a soft gasping sound, so quiet that it takes Hajime a moment to connect the sound with the sudden clench around his fingers, and realise that Oikawa has just come. 

Hajime withdraws his hand slowly, and rolls onto his back to listen to Oikawa's heavy breathing slowly even out. When he says nothing, Hajime reaches down and slips his hand into his own underwear, his heart hammering at the awareness that his fingers are wet half with his own slick, and half with Oikawa's. It doesn't take him long to make himself come, smothering his moan in the pillow. 

When he's finished shuddering, Hajime wipes his fingers on his underwear and turns to look at Oikawa. He's not surprised to see that Oikawa is already asleep, his head turned against the pillow and his mouth hanging open. Hajime reaches over and nudges his jaw closed so that he won't drool on himself, before relaxing into his own blankets, watching the steady rhythm of Oikawa's chest as he too slowly drifts off to sleep.

 

—

 

"Morning, Iwa-chan!"

Hajime pushes himself up slightly with a groan. "Hhhnn?" 

Oikawa laughs. "I said good morning, sleepy-chan!"

Hajime groans again, then throws a pillow at him. 

Oikawa catches it, laughing. "Come on, smelly Iwa-chan. I'm not feeding you unless you get out of bed."

"If I smell, it's _your fault_ for rubbing all over me last night," Hajime grumbles. Complaint voiced, he rolls out of the futon and pushes past Oikawa, staggering to the bathroom. There's no use telling Oikawa how much Hajime _likes_ his sweet, fresh scent, or the way it reminds him of aloe drink and fresh cut grass and summers playing baseball and volleyball in the park. Telling him would only inflate his already obnoxious ego. Shaking his head, Hajime leans over the sink and splashes his face with water. And then he _remembers_. 

"Oh, fuck."

He glances down at himself, at his underwear covered in dried streaks, and winces. They had sex. Oikawa made them have _sex_. It's typical of him; rushing into something without considering where it will take them. Hajime groans and scrapes his fingers through his hair, his mind racing. Does Oikawa want to date? Does he just want to be heat mates? Was he just curious and horny and couldn't contain it any longer?

When Hajime stomps back into Oikawa's bedroom, Oikawa beams up at him from where he's sitting on Hajime's folded up futon. 

"You took forever in there!" Oikawa chides. He gives Hajime a nasty look, winking at him again. "Were you jerking off after all?"

Hajime scowls at him. "As if we didn't get enough of that last night," he snaps, the words out before he can stop them. He shuts his mouth immediately, but the damage is already done, and the back of his neck begins to burn. 

"I _told you_ ," Oikawa says, rolling his eyes. "I didn't do anything in the bathroom. You're such a prude, Iwa-chan."

"Not the bathroom," Hajime growls. "After that, in bed!"

Oikawa blinks at him. "I wouldn't do that."

"What—wouldn't do what?" Hajime asks, frowning. 

"Wouldn't jerk off next to you!" Oikawa says, exasperation creeping into his tone. 

Hajime throws his hands up. "Right, so getting off in the next bed is frowned upon, but dry humping me is totally okay."

Oikawa's eyes round almost comically. "Dry—wait, _what_?"

"Last night!" Hajime whisper-shouts, aware that he's starting to sound hysterical. The last thing he needs is Oikawa's parents overhearing. "When you started—" Hajime's face gets very warm. "When you were—grinding on me," he mumbles. 

Oikawa's nose wrinkles. "I did nothing of the sort."

"You did! Right before you started groping my chest."

"Iwa-chan!" Oikawa protests, looking half amused and half outraged. "If this is your way of telling me I'm being too clingy—"

"Why are you pretending it didn't happen, bastard?" Hajime hisses. "You came and everything."

Oikawa's mouth, already open to argue with him, snaps shut. His eyes widen again. "Oh," he says, very softly.

"Yeah, 'oh'," Hajime says crossly. He folds his arms, letting a little of the smugness show on his face. That'll teach Oikawa to try and pretend nothing happened. 

Oikawa swallows, then licks his lips. "How do you know I—" He trails off, but his crimson ears give him away. 

Hajime's own face feels volcanic, but he shoves aside embarrassment to focus on annoyance instead. "How do I fucking know? I had my fucking fingers inside you when you did, stupid," Hajime snarls. "So don't tell me you don't remember it, because—"

"I was asleep," Oikawa whispers. 

Hajime stares at him. "Bullshit."

But Oikawa doesn't look like he's lying. Even if he was, his scent is a dead giveaway; the sharp, peppery smell that starts to overlay the fresh sweetness is all too familiar of Oikawa with anxiety, Oikawa cornered and trying to think his way out of it. He licks his bottom lip again, his eyes darting away and then back to Hajime's face. "I think—I was asleep. I don't remember it, but—" He looks away again. "I did wake up feeling, um. Really good. And, uh—really— _wet_."

The heat drains from Hajime's face. "You used to sleepwalk."

Oikawa looks slightly put out. "I haven't done it in years."

"I forgot—I thought—I thought you were awake."

Oikawa drags his bottom lip through his teeth, and takes a shaky breath. "You—" He breaks off and covers his face, so the rest of his sentence comes out muffled, but unfortunately still audible. "You had your fingers inside me?"

Hajime tries to swallow, but it feels like there's a tennis ball in his throat. "Well," he grits out. "I'm gonna go to school and throw myself off the activities building."

"No—o," Oikawa whines, reaching out to snag his ankle when he backs away a few steps. "Iwa-chan, wait."

Hajime chokes. "Wait!? I—I literally molested you, Tooru." He groans and drops to a crouch, cradling his head in his arms. "Oh god, I'm—fuck, I'm so sorry."

"Iwa-chan, come on—"

"I—I can't believe I did that." He lifts his head, turning a wild-eyed look toward Oikawa. "This is a joke, right?"

Oikawa bites his lip again, and shakes his head. "But, Iwa-chan—"

Hajime covers his face again, groaning loudly. "I'm a horrible human being. I'm a total fuckboy. I'm so sorr—"

 _"Iwa-chan,"_ Oikawa hisses, reaching out and seizing his shoulders. He gives Hajime a gentle shake. "Pull yourself together, would you? From the sounds of it, I was the one who started it anyway."

"Oikawa—" 

"No," Oikawa says, shaking his head firmly. "I know you wouldn't...do that on purpose."

Hajime scowls. "Of course I wouldn't!"

"And it's not anything I wouldn't want to do anyway," Oikawa goes on, his voice becoming smaller and harder to hear. "With Iwa-chan, I mean."

"What—what the fuck is that supposed to mean?" Hajime asks, squinting at him. 

Oikawa swallows heavily. His face slowly turns from pink to scarlet. "Well, I don't make out with you every other week because it's horrible, Iwa-chan."

There must be words in Hajime's head, somewhere, but he can't seem to find any of them. He opens his mouth and closes it again, and the whole time Oikawa watches him from under lowered eyelashes. 

"You—" Hajime finally manages, his voice dropping to a scandalised whisper. "You want to have sex? With me?"

Oikawa nods. "I should've thought that was obvious after last night, grumpy-chan."

Hajime shakes his head, wincing. "But—what I did to you, I—"

"Should do it again," Oikawa says firmly, blinking up at him. "You should do it again, Iwa-chan."

"But—"

Oikawa grabs his face and kisses him firmly. "I want to _remember_ it, silly," he murmurs, holding Hajime's face close to his own. His breath is minty, his eyes heavy. "Can we do it again? Please?"

Hajime swallows thickly. "Well, yeah…"

The smile Oikawa gives him in response makes Hajime's stomach turn over. "Can we try right now?"

"What? No!"

"Don't worry," Oikawa whispers. "It's early, and I'll think of a way to keep you quiet. Mama won't hear."

Hajime flushes. "That's not what I'm worried about!"

"Come on, Iwa-chan," Oikawa murmurs, pulling him down onto his own messy futon. "Show me what I missed."

"Oikawa—"

"Besides," Oikawa interrupts, nuzzling against Hajime's neck, stimulating the scent gland below his ear. "You need to let me return the favour."

**Author's Note:**

> [tumblr](https://notallballs.tumblr.com/) | [twitter](https://twitter.com/notallbees) | [my iwaoi fic](https://archiveofourown.org/works?utf8=%E2%9C%93&commit=Sort+and+Filter&work_search%5Bsort_column%5D=revised_at&work_search%5Brelationship_ids%5D%5B%5D=1329922&work_search%5Bother_tag_names%5D=&work_search%5Bquery%5D=&work_search%5Blanguage_id%5D=&work_search%5Bcomplete%5D=0&fandom_id=758208&user_id=notallbees)
> 
>    
>  **Warnings:**
> 
> **a)** Iwa initiates sex with a sleeping Oikawa, thinking that Oikawa is awake and is trying to initiate sex with him. He brings Oikawa to orgasm while he's still asleep. Oikawa is fine with this after he wakes up, but there's no consent given beforehand.
> 
>  **b)** This fic may also be triggering for those with gender dysphoria.
> 
> So I write Alpha, Omega or Beta as the primary gender designation and Male/Female as the second. So alphas usually have dicks (in the case of female alphas, they're essentially repurposed clits). Omegas usually have vaginas/uteruses etc (honestly I just can't not think about ass babies and I refuse to have a world with ass babies) and male omegas often have large clits that are basically vestigial penises. 
> 
> Ignore all of that if it makes you uncomfortable, or if you really love ass babies.


End file.
